An x-ray image of the sun, taken by the soft x-ray telescope (SXT) on board
the Yohkoh spacecraft. A high resolution GIF image can be found
here.
From the Yohkoh SXT web page:

The Extended Solar Corona

This is an X-ray image of the sun taken on 8 May August 1992. The image was made
up from two pointings of the spacecraft, one to the east and one to the west, to
capture the distant corona far above the sun's limb.
This version of the image has been corrected for instrumental effects and
processed to enhance various solar features.

The Yohkoh/SXT teams request that the following information be included
when these images are used:

The solar x-ray images are from the Yohkoh mission of ISAS, Japan. The x-ray
telescope was prepared by the Lockheed Palo Alto Research Laboratory, the
National Astronomical Observatory of Japan, and the University of Tokyo with the
support of NASA and ISAS.